An existing double-glass module uses tempered glass as a backplane, where a front surface uses EVA or PVB with a high UV transmittance, and a back surface uses a white EVA or PVB layer. The above double-glass module has following defects.
First, the back of the double-glass module uses airtight and waterproof glass, which can prevent water vapor from entering the module. However, a gap between edges of two pieces of glass is still a weak point, and water vapor can still enters the module by passing through an encapsulation film. Because of an airtight effect of glass, it is difficult for the water vapor to spread out. At the action of ultraviolet light, an EVA encapsulation film is degraded to produce a small acetic acid molecule, which can still erode a cell, and reduce a service life of the module. If the module is PVB encapsulated, because PVB has high water absorption, the problem is more severe.
Second, with the use of the white EVA or PVB layer in the back surface, a problem is that the white part may spread to the front surface of the cell after a long time of use and, thus, may block the cell, and cause a hot spot, affecting module efficiency.
Third, potential risks exist when the module has no frame, because edges and corners are the most fragile parts of tempered glass. If improperly protected, the module is very easily cracked.
Moreover, currently, a disclosed solar photovoltaic module includes: a glass layer, a front layer adhesive film, a plurality of cells that are disposed in arrays at intervals, a back layer adhesive film, and a photovoltaic backplane. The photovoltaic backplane includes a specular reflection part covered by a cell and a diffused reflection part located at a gap between cells, where a cross section disclosing the diffused reflection part is an isosceles trapezoid or the diffused reflection part is a spherical diffused reflection part. However, because a reflection layer is in a structure of an isosceles trapezoid, when an upper bottom surface is directly exposed in sunlight, the light is directly reflected off, and the light cannot be utilized, affecting photoelectric conversion efficiency. On the other hand, because the reflection layer is in a structure of a trapezoid, during a lamination process, edges and corners of the trapezoid inevitably cause some damage to an encapsulation film and a cell edge, thereby reducing a service life of the entire solar cell module.